Although my knowledge is quite limited on this subject, I believe they are two completely different strains, eventhough they have more similarities in that family of organisms than the others.
If my thoughts are right, the Lactobacilli just sours or taints the beer a little, the Pediococci would completely spoil it.
I'm sure Mesa can give you a better, and more informed answer.

Everyonr here would rather not even try to have pediococci anywhere aroung there brew supplies. You probably should speak to you professor about your findings, or questions. Be careful with the growing of that or any bacteria, I'm sure they could be dangerous in large numbers. We try to clean everything with different solutions so bacteria doesn't breed, except when brewing belgian wheat beer, and that is just the Lacto strain.